Photolithography is a process used in fabrication of nanoscale components (e.g., electrical circuits, optical components) that are generally made of thin films layered on a substrate. This process involves depositing thin film layer(s) on a substrate, forming geometric pattern formed with a layer of photoresist material, and then selectively removing parts of a thin film (or the substrate itself) based on the geometric pattern.
During the photolithography process, electromagnetic energy (e.g., light) is transmitted through a photomask or reticle to expose parts of the photoresist layer in the desired pattern. The exposed photoresist can be subjected to a chemical treatment (e.g., “developing”) that removes areas of photoresist that were exposed to the light. In other cases, areas receiving no light exposure may instead be removed by a developer. In either case, the resulting surface has a pattern formed by the developed photoresist, and the surface can then be further treated. For example, etching may be performed so that exposed areas of the surface are etched away, while those areas covered by the photoresist are unaffected.
Photolithography is commonly associated with the manufacture of an integrated electronic circuit. Photolithography can also be used in making integrated optics, which includes optical components (e.g., lasers, waveguides, lenses, mirrors, collimators, etc.) that are formed on a substrate in a manner analogous to integrated electrical circuits. Photolithography is also used in manufacturing recording head components for data storage devices.